Presentation on theme: "By: Jasmine Ahmed, Shelley Bi, Christina Bai"— Presentation transcript:
1 By: Jasmine Ahmed, Shelley Bi, Christina Bai Free FallBy: Jasmine Ahmed, Shelley Bi, Christina Bai
2 What is Free Fall?Free fall is the motion of an object falling with a constant accelerationIn this case, the constant acceleration would be a = g = 9.81 m/s2, but since objects free fall towards the Earth's surface ---> a = - g = m/s2 When there is no air resistance, all objects fall with the same acceleration regardless of their masses
3 For Example . . .If an astronaut dropped a hammer and a feather in space, the hammer and the feather would fall towards the surface with the same acceleration, therefore they would land on the surface at the exact same time.
4 In free fall, the acceleration, 9. 81 m/s2, remains constant In free fall, the acceleration, 9.81 m/s2, remains constant. This occurs, because of the gravity near the Earth's surface. V = at
5 To find the distance traveled by an object during free fall, we use the formula, where a=g d= vit + 1/2 at2When an object starts at rest, the formula is reduced to d= 1/2 at2, because the velocity is 0 m/s.
6 Problem 1A ball dropped from rest falls freely until it hits the ground with a speed of 20 meters per second. The time during which the ball is in free fall is approximately (1) 1 s (2) 2 s(3) 0.5 s(4) 10 s
7 Solution to Problem 1 V = at t = V a t = 20 m/s -9.81 m/s^2 (2) t = 2 seconds
8 Problem 2An object is allowed to fall freely near the surface of a planet. The object has an acceleration due to gravity of 24 m/s2 How far will the object fall during the first second? (1) 24 meters (3) 9.8 meters (2) 12 meters (4) 4.9 meters
9 d= 1/2 at2 d= 1/2 (24 m/s2)(1s) (2) d= 12 m Solution to Problem 2d= 1/2 at2 d= 1/2 (24 m/s2)(1s) (2) d= 12 m
10 Problem 33. Starting from rest, object A falls freely for 2.0 seconds, and object B falls freely for 4.0 seconds. Compared with object A, object B falls (1) one-half as far (3) three times as far (2) twice as far (4) four times as far
11 Solution to Problem 3 d= 1/2 at2 d= 1/2(-9.81m/s2)(2s)2 d= 19.62 m d= m (4) four times as far